.NET Framework Class Library
File..::.Copy Method (String, String)

Updated: July 2009

Copies an existing file to a new file. Overwriting a file of the same name is not allowed.

Namespace:  System.IO
Assembly:  mscorlib (in mscorlib.dll)
Syntax

Visual Basic (Declaration)
Public Shared Sub Copy ( _
    sourceFileName As String, _
    destFileName As String _
)
Visual Basic (Usage)
Dim sourceFileName As String
Dim destFileName As String

File.Copy(sourceFileName, destFileName)
C#
public static void Copy(
    string sourceFileName,
    string destFileName
)
Visual C++
public:
static void Copy(
    String^ sourceFileName, 
    String^ destFileName
)
JScript
public static function Copy(
    sourceFileName : String, 
    destFileName : String
)

Parameters

sourceFileName
Type: System..::.String
The file to copy.
destFileName
Type: System..::.String
The name of the destination file. This cannot be a directory or an existing file.
Exceptions

ExceptionCondition
UnauthorizedAccessException

The caller does not have the required permission.

ArgumentException

sourceFileName or destFileName is a zero-length string, contains only white space, or contains one or more invalid characters as defined by InvalidPathChars.

-or-

sourceFileName or destFileName specifies a directory.

ArgumentNullException

sourceFileName or destFileName is nullNothingnullptra null reference (Nothing in Visual Basic).

PathTooLongException

The specified path, file name, or both exceed the system-defined maximum length. For example, on Windows-based platforms, paths must be less than 248 characters, and file names must be less than 260 characters.

DirectoryNotFoundException

The path specified in sourceFileName or destFileName is invalid (for example, it is on an unmapped drive).

FileNotFoundException

sourceFileName was not found.

IOException

destFileName exists.

-or-

An I/O error has occurred.

NotSupportedException

sourceFileName or destFileName is in an invalid format.

Remarks

This method is equivalent to the Copy(String, String, Boolean) method overload with the overwrite parameter set to false.

The sourceFileName and destFileName arguments are permitted to specify relative or absolute path information. Relative path information is interpreted as relative to the current working directory. To obtain the current working directory, see GetCurrentDirectory.

For a list of common I/O tasks, see Common I/O Tasks.

Examples

The following example copies files to the C:\archives\2008 backup folder. It uses the two overloads of the Copy method as follows:

  • It first uses the File..::.Copy(String, String) method overload to copy text (.txt) files. The code demonstrates that this overload does not allow overwriting files that were already copied.

  • It then uses the File..::.Copy(String, String, Boolean) method overload to copy pictures (.jpg files). The code demonstrates that this overload does allow overwriting files that were already copied.

Visual Basic
Dim sourceDir As String = "c:\current"
Dim backupDir As String = "c:\archives\2008"

Try
    Dim picList As String() = Directory.GetFiles(sourceDir, "*.jpg")
    Dim txtList As String() = Directory.GetFiles(sourceDir, "*.txt")

    ' Copy picture files.
    For Each f As String In picList
        'Remove path from the file name.
        Dim fName As String = f.Substring(sourceDir.Length + 1)

        ' Use the Path.Combine method to safely append the file name to the path.
        ' Will overwrite if the destination file already exists.
        File.Copy(Path.Combine(sourceDir, fName), Path.Combine(backupDir, fName), True)
    Next

    ' Copy text files.
    For Each f As String In txtList

        'Remove path from the file name.
        Dim fName As String = f.Substring(sourceDir.Length + 1)

        Try
            ' Will not overwrite if the destination file already exists.
            File.Copy(Path.Combine(sourceDir, fName), Path.Combine(backupDir, fName))

            ' Catch exception if the file was already copied.
        Catch copyError As IOException
            Console.WriteLine(copyError.Message)
        End Try
    Next

    For Each f As String In txtList
        File.Delete(f)
    Next

    For Each f As String In picList
        File.Delete(f)
    Next

Catch dirNotFound As DirectoryNotFoundException
    Console.WriteLine(dirNotFound.Message)
End Try
C#
string sourceDir = @"c:\current";
string backupDir = @"c:\archives\2008";

try
{
    string[] picList = Directory.GetFiles(sourceDir, "*.jpg");
    string[] txtList = Directory.GetFiles(sourceDir, "*.txt");

    // Copy picture files.
    foreach (string f in picList)
    {
        // Remove path from the file name.
        string fName = f.Substring(sourceDir.Length + 1);

        // Use the Path.Combine method to safely append the file name to the path.
        // Will overwrite if the destination file already exists.
        File.Copy(Path.Combine(sourceDir, fName), Path.Combine(backupDir, fName), true);
    }

    // Copy text files.
    foreach (string f in txtList)
    {

        // Remove path from the file name.
        string fName = f.Substring(sourceDir.Length + 1);

        try
        {
            // Will not overwrite if the destination file already exists.
            File.Copy(Path.Combine(sourceDir, fName), Path.Combine(backupDir, fName));
        }

        // Catch exception if the file was already copied.
        catch (IOException copyError)
        {
            Console.WriteLine(copyError.Message);
        }
    }

    // Delete source files that were copied.
    foreach (string f in txtList)
    {
        File.Delete(f);
    }
    foreach (string f in picList)
    {
        File.Delete(f);
    }
}

catch (DirectoryNotFoundException dirNotFound)
{
    Console.WriteLine(dirNotFound.Message);
}

.NET Framework Security

Platforms

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC, Xbox 360, Zune

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
Version Information

.NET Framework

Supported in: 3.5, 3.0, 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 3.5, 2.0, 1.0

XNA Framework

Supported in: 3.0, 2.0, 1.0
See Also

Reference

Other Resources

Change History

Date

History

Reason

July 2009

Replaced the code example.

Customer feedback.

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